Method and apparatus for sonic jarring with fluid drive



Feb. 2, 1965 A. G. BODINE, JR 3,168,140

METHOD AND APPARATUS FOR SONIC JARRING WITH FLUID DRIVE 2 Sheets-Sheet 1Original Filed Feb. 20, 1956 INVENTOR. ALBERT G. BODINE JR.

ATTORNEYS Feb. 2, 1965 A. G. BODINE, JR 3,168,140

METHOD AND APPARATUS FOR some JARRING WITH FLUID DRIVE Original FiledFeb. 20, 1956 2 Sheets-Sheet 2 FIG.4 F|G.5

22! INVENTOR.

AL B ERT G. BODINE JR.

ATTORNEYS United States Patent Ofifice 3,158,140 Patented Feb. 2, 19653,168,140 METHOD AND APPARATUS FOR SONIC JARRING WITH FLUID DRIVE AlbertG. Bodine, Jr., Sherman Oaks, (Zalif. (7877 Woodley Ave., Van Nuys,Calif.)

Original application Feb. 20, 1956, Ser. No. 566,620, new Patent No.2,972,380, dated Feb. 21, 1961. Divided and this application Dec. 22,1960, Scr. No. 77,670

3 Claims. (Cl. 166-46) This invention relates generally to methods andapparatus'for loosening and/or pulling or removing elongated objectsstuck or frozen by static friction in other objects, for example, pipesuch as liners, casing, drill pipe, sucker rods and pump plungers, orother objects or fish which have become stuck by static friction in oilwells. It relates, in a still broader aspect, to longitudinal movementof elogna-ted members in a surrounding medium, and accordingly, isapplicable not only to removal of stuck members, as pipe fast in a wellbore, but to driving frictionally bound members downwardly in the well,and, in another application, to driving of piles into the earth.

One primary object of the invention is the provision of improved methodsand apparatus for loosening and/ or moving frictionally stuck or boundmembers by transmitting acoustic waves therethrough under conditions ofstanding wave resonance, utilizing novel apparatus and procedures bywhich very tightly bound members may be readily broken loose andremoved, or driven deeper.

This application is a division of my parent application, Serial No.566,628, filed February 20, 1956, now Patent No. 2,972,380, entitledAcoustic Method for Moving Objects Held Tight Within a SurroundingMedium.

The invention provides for setting up in the elongated stuck object aresonant acoustic longitudinal standing wave of high amplitude, therebycausing a cyclic force in a longitudinal direction to be exerted by theobject in the cement, or other surrounding holding medium, at the stuckpoint, as well as a cyclic elastic contraction and expansion of theobject at the stuck point, which is at a velocity node of the standingwave. Impedance mismatch and phase differences between the object andthe surrounding media in which the same is frozen prevent thesurrounding media from contracting and expanding either in step with orto the same degree as that which the stuck region of the object mayreadily undergo under proper drive. Frictional resistance losses in anymedia also results in failure to transmit the alternate expansion andcontraction from the stuck object to the media without material loss ofamplitude. The lesser amplitude of the periodic contraction andexpansion of the surrounding media means that the stuck object is clearof the media for a time during each contraction half cycle. Moreover,phase difference between the expansion and contraction cycles of thestuck object and the surrounding media means that the object isundergoing contraction during at least a part of the time that thesurrounding media is undergoing its expansion halfcycle, with resultingstill greater momentary clearance. In effect, the surrounding mediastand back while the stuck object periodically contracts. Such actionrapidly loosens the stuck or frozen object, and it may then be elevatedby pulling upwardly on it. It is often desirable to pull upwardly on theobject while it is undergoing its cyclic motion relative to thesurrounding media, with the result that it moves upwardly by smallincrements as successive momentary clearances occur. In other cases, itis found preferable to permit the object, or a large longitudinalfraction thereof, to stand in compression, with the result that theobject moves downward as it is loosened. After complete loosening, it

maybe readily elevated. A feature of the invention is the control of thetension and/or compression in the casing to accomplish most advantageousperformance in any given case.

In order to achieve the above described loosening action, I have foundit necessary to transmit relatively powerful acoustic waves down thefrozen rods, pipe, fish, etc., to the site where the object is stuck inthe cement, or other holding medium, whereby to develop cyclic forcesworking against and overcoming the holding strength of the cement orother holding medium on the stuck object, and to accomplish this,certain novel relationships between the source of the acoustic waves,the stuck object, and any supporting means for the equipment, have beenfound to be of prime importance. In this connection, I utilize theconcept of mechanical impedance, which, in this case, signifies theratio of total cyclic peak force to displacement velocity at any givenpoint in the acoustic wave system. The stuck region of the object is aregion of high impedance, being at a velocity node of the standing wavesystem, while the upper end of the object is a region of lowerimpedance, being at a velocity antinode of the standing wave system. Theacoustic wave source may be a very powerful mechanical vibrator. Now, Ihave found that it is of utmost importance, if the necessary substantialpower for tightly stuck jobs is to flow from the wave generator into theobject in which the standing wave is to be developed, that the couplingbetween the generator and the object have an acoustic impedance which isof at least as high an order of magnitude as that of the upper endportion of the object at the coupling point. This impedance requirementmay be met by use of a firm or rigid coupling means, for exampleserrated wedge slips, or mechanical clutch jaws, acting directly betweenthe generator case or frame and the object. A low impedance couplingi.e., of lower order than that of the upper end of the object,involving, for instance, a flexible element, such as a common suspensioncable, or the like, lacks the ability to transmit the high cyclic forcethat is available from the necessary high power generator, and apply itto the pipe. Thus a high impedance coupling, i.e., one of an impedancemagnitude of an order comparable to that of the upper end portion of theobject at the point Where the coupling is to be made thereto, is anabsolute requisite, and is satisfied by any mechanical coupling deviceof suificiently high impedance. I sometimes prefer for this purpose acoupling device comprising well known serrated wedge slips rigidlyconnected with the generator and engaged directly with the object.

Also any supporting or suspension means for the acoustic wave generatormust, I have found, have a relatively low mechanical impedance, and maybe a flexible cable, desirably including a spring vibration-isolator, orother relatively compliant element, so as to prevent materialtransmission of vibratory power through such supporting or suspensionmeans.

Still further, I have found it highly important to employ an acousticwave generator which is operable at a resonant frequency of the stuckobject, and one whose output impedance is comparable to the impedance ofthe object at the point of coupling thereto.

An important incident of the setting up of the described resonantacoustic standing wave in the pipe or other member to be loosened is anenergy storage property inherent in resonant systems of the character inquestion. A large quantity of acoustic energy is periodically deliveredto the vibrating pipe or rod string, stored therein, and periodicallyreleased therefrom so as to deliver large cyclic forces to the stuckpoint. The resonant pipe or rod string thus inherently functions as alarge energy storage reservoir, giving the system a high Q factor, i.e.,large flywheel effect, comparable to the tank circuit of an electricoscillator, and assuring large energy delivery and corresponding forceapplication to the stuck region of the object to be loosened.

A particular form of my invention specifically covered in thisdivisional application embodies a fluid-driven mechanical wave generatoror oscillator for setting up the sonic wave action in the elongatedstuck object. My fluid drive system inherently possesses a certaindegree of softness, flexibility or mushiness in its transmisioncharacteristics that is unfortunately lacking in purely mechanicaldrives, which tend toward roughness in operation. The fluid drivenoscillator is thus better able to run smoothly at the resonantfrequency.

Particularly when the oscillator is in a down-hole loca tion, a fluidtransmission column from ground surface to oscillator is of uniqueadvantage. Such a long fluid column permits the down-hole oscillator tolock-in at various resonant frequencies with increased facility, in viewof the yield or give in the fluid column. The oscillator is, in otherwords, because of the soft or flexible fluid link, fairly independent offlow irregularities of the fluid pump (usually a conventional piston mudpump) at the ground surface. As a matter of fact, assuming such a mudpump, and the use of drilling mud as a fluid drive medium, thealternating or reciprocating mud flow near the pump becomessubstantially continuous flow at the down-hole oscillator. In addition,the fluid column affords a large energy storage reservoir, which tendstoward stabilizing the operation ofthe oscillator, supplying always justthe energy required for uniform oscillator operation.

An object of the invention is accordingly the provision of a fluiddriven sonic jar.

The invention will be further understood from the following detaileddescription of a number of related illustrative embodiments, referencefor this purpose being had to the accompanying drawings, in which:

FIG. 1 is a view, partly in elevation and partly in vertical medialsection, showing an illustrative form of the invention adapted forloosening a string of well pumping sucker rods; 7

FIGS; 2 and 3 are sections on lines 2--2 and 33, respectively, FIG. 1.

FIG. 4 is an elevation of another embodiment of the invention;

FIG. 5 is a section taken on line 55 of FIG. 4;

FIG. 6 is a vertical medial section showing a modificaof FIG. 5; and

FIG. 7 is a section on line 77 of FIG. 6.

, FIGS. 13 illustrate an embodiment of the invention designed for thepurpose of loosening an elongated elastic object or column, in this casean oil well sucker rod string and or pump plunger frozen in a well bysand or other conditions. The upper end portion of the sucker rod string129, above well-head 130, known usually as the polished rod, isindicated at 131, and clamped thereto as by means of clamp 132, is anacoustic wave generator or oscillator 133. It will be understood thatthe sucker rod string 129 and deep well oil pump below the wellhead maybe of any conventional type. Numeral 134 designates a hook understoodtobe suspended by conventional derrick tackle, by, which it may beraised and lowered, and

this hook engages a bail 135 carrying the casing 136 of a low impediancespring isolator 136a.. A suspension rod 137 is reciprocable through anopening in the bottom of casing 136 and has at its upper end a head 139supported on the upper end of coil spring 140 whose lower endiissupported on the lower end of casing 138. The lower end of rod 137carries a socket 142 which receives the'upper extremity of rod .131, andthis socket is equipped with a clamp 143 adapted to 'clamp r-od131.rigid1y within the socket. As here shown, the socket may have a halfround bore 144 adapted to snugly receivethe upperextremity of thepolished rod 131, and with an enlarged half round bore 145 adapted toaccommodate arcuate clampmem 4 ber 146 which engages the rod and clampsit by means. of screws 147.

The vibration generator 133 includes a housing 150 formed with a halfround seat 151 (FIG. 3) adapted to engage the rod 131, and with aprojecting arm 152 in which is mounted clamp screws 153 adapted toengage arcuate clamping member 154 engaging the rod 131 and clamping ittightly to its seat 151.

The generator housing 150 has a vertical fluid cylinder 155 formed witha bore 156 in which is fitted a linearly reciprocating piston 157positioned between coil compression centering springs 158 bearingagainst caps 159 screwed into opposite ends of bore 156. The caps 159are bored and threaded to receive air hose fittings 160 which areconnected by air hoses 161 to' opposite ends of air cylinder 162. Apiston 163 in cylinder 162 is reciprocated by connecting rod 164 drivenfrom eccentric 165 on a shaft 166, which may be powered by and suitableat the other end thereof. On the opposite stroke of piston 163, thereverse takes place. Accordingly, piston 157 is caused to oscillatelinearly within cylinder 156 between springs 158, which alternatelyelongate and contract to accommodate the action, and act to retard andstop the piston at the ends of the stroke.

The described linear oscillation of piston 157, whose mass acts on theend caps 159 of the cylinder through springs 158, results in alternatingvertical reactive forces being exerted against the generator housing,and therefore on the sucker rod string to which it is rigidly clamped.The upper end portion of the sucker rod string is thereby verticallyoscillated, and longitudinal acoustic waves are accordingly set up inthe sucker rod string, and transmitted to the site where the string orpump plunger is frozen within the well. The suspension means asdescribed comprises a low impedance support, the spring isolatorpreventing transmission of vibration energy to the hook and derricktackle above. A biasing force or tension can be exerted in the suckerrod string, assuring efficient transmission of power from the generatorto the rod string.

The acoustic waves, transmitted down the rod string as described abovefrom the oscillator to the point where the rod string or pump plunger isstuck in the well, are reflected from the stuck (stationary) point andreflected back up the rod string. In terms of impedance'the point wherethe rod string or plunger is stuck is apoint of high mechanicalimpedance, and the cyclic stresses in the string or plunger are atmaximum amplitude in that region, 1ongitudinal motion or displacementbeing minimized, or approaching zero. The prime mover driving the airpiston 163 is then operated at a speed which, through the fluid drivesystem, reciprocates piston 157 of oscillator 133 at a frequencyestablishing in the rod string between the stuck point and saidoscillator, a resonant acoustic standing wave of an odd number ofquarter wavelengths, such as represented in FIG. 4 of my aforementionedPatent No. 2,972,380. The operator readily recognizes that he has setthe prime mover todrive the. system at this condition of resonance byobvious and well-known physical manifestations of resonance, includinglarge increases in amplitude of vibration with small variations infrequency, asin all vibratory systems operating at or approachingresonance.

It should be understood that when a resonant longitudinal standing waveis established in a column, which-is stuck or immobilized againstlongitudinal motion at a given point, a velocity node of the standingwave must necessarily occur at the stuck or immobilized point, and

that a cyclic longitudinally-directed force will be exerted inthecolumn, at the node, against the immobilizing medium. It should beunderstood that forces at a node at a free point in a column are opposedand dynamically balanced. When, however, a given column is held fast atan arbitrary point, the resonant standing wave set up in the column willhave a node at the fast point, and, in general, the cyclic forces in thecolumn on the acoustically free side of the fast point will not bedynamically balanced by like forces on. the other side thereof, but willbe exerted against and opposed by the immobilizing medium. Additionally,as mentioned heretofore, the elastic column, in which a longitudinalstanding wave is sustained, alternately elastically dilates andcontracts at the velocity antinode in step with alternating compressiveand tension phases of the wave in the column. This follows from aphenomenon generally referred to as Poissons Ratio, and consists in aradial dilation or contraction of an elastic column in response tocompression or tension exerted in the column.

Returning to a consideration of FIGS. l-3, the longitudinally-directedcyclic forces thus exerted by the rod string or pump plunger on. theholding medium act to overcome the holding strength of the medium. Theal ternating dilations and contractions of the spring act also toovercome the holdingstrength of the medium. In connection with thelatter effect, i.e., alternating dilation and contraction of the string,owing to impedance mismatch between the string and the medium in whichit is frozen, frictional losses between the members, and cyclic phasedisplacements, the cyclic contractions of the string are not followed upby like contractions of the medium in which the string has becomefrozen, and the bond is quickly broken.

A unique advantage in the system of FIGS. 1-3 is the softness orflexibility of oscillator drive afforded by the described fluid drivemeans, contributing toward ability of the oscillator to run smoothly andevenly at the resonant standing wave frequency desired to be establishedin the stuck column or rod string.

In FIGS. 4 and 5 is shown another embodiment of the invention, in thiscase characterized by a gyratory type of down-hole vibration generatoror oscillator in a tool suspended in the well from a string of drillpipe and operated by down-hole turbine means motivated by fluid pumpeddown the drill string from the ground surface. Drilling mud fluid can beused, or crude oil, if available, or Water. Numeral 219 designates thelower end portion of a hollow drill stem suspended in well bore 211, andto the lower end of drill stem 210 is coupled the upper end of a sectionof heavy drill collar 212. Coupled to the lower end of the latter is arelatively slender and flexible pipe section 213, and pipe section 213suspends the vibratory tool 214 by means of a coupling indicated at214a. The tool 214 comprises a mandrel or hollow body 215 containing aturbine driven vibration generator 216.

The body or mandrel 215 is of good elastic material, such as steel, andrelatively thick-walled excepting for an intermediate section 215a,wherein is formed an enlarged cavity 217 for accommodation of generator216, and a lower end section 21517 which is formed with the socket 218of an overshot grappling tool 219. The latter is conventionally shownwith tapered extremity containing wedge slips 220 adapted to rigidlysecure a fish 221.

The generator 216 comprises a cylindrical inertia roller 222 adapted toroll around a cylindric raceway 223 formed inside body section 215a. Thelower end of roller 222 is vertically supported by the curved shouldersof ribs 224 formed inside body 214 at the lower end of the generatorcavity 217, the interior walls of section 215a joining the thick-walledsection below by a tapered surface 225 so as to provide adequateclearance for downward liquid flow from the chamber 217.

Tightly mounted in the upper part of chamber 217, above roller 222, area plurality of vertically spaced turbine stators 230, and between these,on an axial stem 231 extending upwardly from roller 222, are tightlymounted a plurality of turbine rotors 232. Fluid pumped down throughdrill stein 210, inertia collar 212, flexible pipe 213 and into theupperend of body 215, is set into rotation in passing stators 230, andimparts rotation to rotors 232 and therefore to inertia roller 222. Theroller accordingly rolls about raceway 223. It is of interest to notethat, since the diameter of roller 222 is less than the diameter of itsraceway 223 but is greater than the radius of the raceway, it willrotate on its axis at a lesser number of revolutions per second than itsnumber of trips per second around the periphery of the raceway. Any slipbetween the surfaces of the roller and the raceway will affect thisdifference. It is the number of trips per second around the periphery ofthe raceway that determines the frequency of the generator.

The operation of the acoustic wave generator is as follows: The roller222 rolling around the raceway 223 exerts on the body 215 a centrifugalforce, and it will be seen that this force, rotating about thelongitudinal axis of the body 215, elastically bends the surroundingportion of the body, moving it around in a gyratory path. The body 215does not bodily rotate, but has a gyratory action which, upon analysis,will be seen to be the resultant of two perpendicular transverse linearharmonic vibrations in quadrature. A generator of this type is describedmore particularly in my Patent No. 2,960,314. As described in saidpatent, the elastic gyratory deformation of the portion of the body 215surrounding the inertia roller 222 ispropagated by corresponding elasticwaves traveling longitudinally along the body 215. These are transmittedto and along the fish 221 to the site where the latter is stuck in thewell, where the wave is reflected back; and also, in the oppositedirection, into and along the flexible pipe to the point of junction ofthe latter with the end of the heavy inertia collar 212, where the Waveis reflected back. Under such conditions, standing wave resonance isautomatically developed along the body 215, the fish down to the stuckpoint, and the flexible pipe 213 up to the inertia collar 212, with avelocity antinode (region of maximum deformation amplitude) at the siteof the generator, and velocity nodes at the point where the fish isstuck in the well, and at the junction of flexible pipe 213 with collar212. The turbine driven roller is constrained by back reaction from thisresonant system to roll around its raceway at the resonant frequency.The fluid drive system particularly accommodates this resonant frequencyoperation notwithstanding fluctuations in fluid pump operation. Theremay be additional nodes and antinodes in the system under certainconditions, but those described above are characteristic of the system.

The described resonant standing wave developed in the system with avelocity node at the side where the fish is stuck in the well, tendsrapidly to loosen the fish. The gyratory wave action described, whilepropagated longitudinally of the tool string, takes place in atransverse plane. At the location where the fish is frozen in the well,where a velocity node of the wave occurs, the elastic stress magnitudeis maximized, and gyratory motion minimized. Under these conditions, thefish is powerfully worked, and rapidly broken free of whatever has beenholding it fast.

In FIGS. 6 and 7 is shown a modification of the system of FIGS. 4 and 5,being similar to that of FIGS. 4 and 5' excepting for employment of amodified type of gyratory acoustic wave generator. The tool 240 of FIGS.6 and 7 may be considered a substitution for the tool 214 of FIGS. 4 and5, and it will be understood that the device of FIG. 6 may be suspendedfrom a drill string similar to that shown in FIG. 4, and may be equippedwith an inertia collar and a flexible pipe section similar to theelements 212 and 213 of FIG. 4, the upper end of the tool 240 beingunderstood to be coupled to the lower end of a flexible pipe such as213. Further, the lower end portion of the tool 24%) may be formed witha grappling tool, similar in all respects to that provided at the lowerend of the tool 214 of FIGS. 4 and 5.

With the understanding stated in the preceding para graph, the tool 240comprises a hollow body 241, generally similar to the body 214 of FIG.5, the lower portion of which is omitted from FIG. 6. The bore throughthe hollow body 241 has an enlarged cavity 242 in which is contained, atan annular spacing from the corresponding thin wall section of the body,a cylindrical case 243 for an unbalanced or eccentric rotor 244. Thisrotor has at the bottom a shaft 245 mounted in suitable bearings 246placed in the lower end of casing 243, the lower end of the latter beingclosed by a'threaded closure disc. Rotor 244 has extending upwardly fromits upper end a shaft 247, supported in a bearing 248 placed in theupper end of casing 243. The casing 243 has an upper end portion 249formed with suitable packing 250 for shaft 247. The casing 243 ispositioned within the thin wall portion of body 241 by means of ribs 252extending inwardly from body 241 at the top, and similarly by ribs 253at the bottom, the last mentioned ribs being also formed with shouldersat 254 for vertical support of the casing 243.

The rotor shaft 247 carres a plurality of axially spaced turbine rotors258, and above each of these is a stator 259. The stators comprise rims260 tightly seated in the bore of the body 241, and a multiplicity ofradial vanes 261.

The upper extremity of rotor shaft 247, above the hydraulic turbinedescribed in the preceding paragraph, is provided with an outboardbearing at 264, carried within a cup 265, and has an upwardly extendingannular wall 268 forming a chamber 269 which is closed at the top by aflexible diaphragm 270.

Cap 267 has a central aperture 271, which communicates with alongitudinal passage 272 extending longitudinally through rotor 247 andopening at the bottom inside rotor case 243. The cup 265 has at thebottom a suitable packing 273 forming a fluid tight seal with shaft 247.Casing 243 is filled with oil and this oil extends upwardly throughpassageway 272 and aperture 271 into chamber 269. In the operation ofthe apparatus, the hol low pipe string carrying the device 240 is filledwith driving fluid, and the hydraulic static head, of this fluid imposedon the flexible diaphragm 270 pressurizes the oil system and preventsleakage of the external driving fluid into the oil system through thevarious packings.

An inspection of FIG. 6 will reveal that a fluid passage has been formeddownwardly through the tool 40 around the outside of the bearing cup 265to the region of the turbine, and from the lower end of the turbinearound the outside of rotor housing 243 to the downwardly extending borebelow. The fluid is deflected by the stator vanes to drive the rotors ofthe turbine, and therefore the unbalanced inertia rotor 244. Rotation ofthe latter generates a centrifugal force, the reaction of which istransmitted through the rotor shafts, the rotor casing 243, and thesupporting ribs 252 and 253 to the body 241. Apart from the detailedaction of the specific gyratory acoustic wave generator of FIG; 6, thesystem is the same as that of FIGS. 4 and 5, and the description neednot be repeated.

The several embodiments now disclosed are representative of fluid drivenoscillators in acoustically vibratory jars, and will be seen to have theadvantages stated in the introductory paragraphs of this specification.

The down-hole oscillator embodiments of FIGS. 4-7, with their long fluidcolumn drive means, afford a large degree of softness or flexibility ofoscillator drive, which permits smooth and even oscillator operation atthe resonant frquency of thesystem, notwithstanding irregularities offluid pumping action at the ground surface.

The invention has now been described through illustration of a number ofillustrative embodiments; It is to be understood, of course, that theseare merely illustrative of various different inventive forms in whichthe broad invention may be embodied, and are not to be considered asexhaustive of the complete range of equivalents coming within the broadscope of the appended claims.

I claim:

1. The method of moving a column system embodying a portion held fast inthe earth and a portion extending therefrom which is acoustically freeand in a condition to sustain a vibration wave pattern, that comprises:acoustically coupling a fluid-drive vibrator to said acoustically freeportion of said column system at a point spaced from said held portion,and fluid driving said vibrator at a frequency which produces resonanceof said column system and which establishes a vibration pattern withcyclic impulse force in said column system within the region of saidheld portion, said resonant frequency and said vibration pattern beingestablished independently of minor irregularities in fluid drive effortby reason of inherent fluid drive flexibility.

2. The method of moving a column system embodying a portion held fast inthe earth and a portion extending therefrom which is acoustically freeand in a condition to sustain a vibration wave pattern, that comprises:acoustically coupling a fluid-drive vibrator to said acoustically freeportion of said column system at a point spaced from said held portion,then applying a bias force to said column system tending to free saidheld portion thereof from the earth, and simultaneously fluid-drivingsaid vibrator at a frequency which produces resonance of said columnsystem and which establishes a vibration pattern with cyclic impulseforce in said column system within the region of said held portion,whereby said bias force and said cyclic impulse force act in combinationto move said column system against the holding resistance of the earth.

3. The method of moving a column system embodying a portion held fast ina bore in the earth deep below ground level, and a portion extendingupwardly therefrom which is acoustically free and in a condition tosustain a vibration wave pattern, that comprises: lowering into saidbore and acoustically coupling to said acoustically free portion of saidcolumn system at a point thereon spaced from said held portion, afluid-drive vibrator, and pumping fluid from the ground level down saidbore to said fluid-drive vibrator at a rate to drive said vibrator at afrequency which produces resonance of said column system and whichestablishes in said system a vibration pattern with cyclic impulse forcein said column system in the region of said held portion thereof, saidresonant frequency and said vibration pattern being established independently of minor irregularities in fluid-drive effort by reason ofinherent fluid-drive flexibility.

References Cited in the file of this patent UNITED STATES PATENTS2,667,932 Bodine Feb. 2, 1954 2,670,801 Sherborne Mar. 2, 1954 2,730,176Herbold Jan. 10, 1956 2,808,887 Erwin Oct. 8, 1957 2,972,380 Bodine Feb.21, 1961

1. THE METHOD OF MOVING A COLUMN SYSTEM EMBODYING A PORTION HELD FAST INTHE EARTH AND A PORTION EXTENDING THEREFROM WHICH IS ACOUSTICALLY FREEAND IN A CONDITION TO SUSTAIN A VIBRATION WAVE PATTERN, THAT COMPRISES:ACOUSTICALLY COUPLING A FLUID-DRIVE VIBRATOR TO SAID ACOUSTICALLY FREEPORTION OF SAID COLUMN SYSTEM AT A POINT SPACED FROM SAID HELD PORTION,AND FLUID DRIVING SAID VIBRATOR AT A FREQUENCY WHICH PRODUCES RESONANCEOF SAID COLUMN SYSTEM AND WHICH ESTABLISHES A VIBRATION PATTERN WITHCYCLIC IMPULSE FORCE IN SAID COLUMN SYSTEM WITHIN THE REGION OF SAIDHELD PORTION, SAID RESONANT FREQUENCY AND SAID VIBRATION PATTERN BEINGESTABLISHED INDEPENDENTLY OF MINOR IRREGULARITIES IN FLUID DRIVE EFFORTBY REASON OF INHERENT FLUID DRIVE FLEXIBILITY.